[PATCH] drivers/serial/serial_core.c: prevent readinguninitialized stack memory

From: Dan Rosenberg
Date: Wed Sep 15 2010 - 17:50:51 EST

The TIOCGICOUNT device ioctl allows unprivileged users to read
uninitialized stack memory, because the "reserved" member of the
serial_icounter_struct struct declared on the stack is not altered or
zeroed before being copied back to the user. This patch takes care of

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@xxxxxxxxx>

--- linux- 2010-08-26 19:47:12.000000000 -0400
+++ linux- 2010-09-15 13:57:04.767375072 -0400
@@ -1081,6 +1081,8 @@ static int uart_get_count(struct uart_st
struct uart_icount cnow;
struct uart_port *uport = state->uart_port;

+ memset(&icount, 0, sizeof(struct serial_icounter_struct));
memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));

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